Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations provide readOnlyHint=true, and description adds OAuth requirement, user-specific data limitation, privacyMode behavior, and read-only nature. No contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Well-structured with purpose first, then details. Slightly verbose but every sentence adds value. Could be shortened without loss.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers all necessary aspects: purpose, prerequisites (OAuth), return value, parameters, privacy mode, and relationship to sibling tools. No output schema needed for this list operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter (privacyMode) with 100% schema coverage. Description adds context beyond enum values: explains defaults and effect on returned data. Slightly redundant with schema description but clear.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Description uses specific verb 'list' and resource 'portfolios', explains it returns computed summaries, and distinguishes from siblings by stating 'start here when a portfolio question doesn't name a specific portfolio'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states when to use (user refers to 'their' portfolios/holdings) with examples. Provides clear context: start here, then pass portfolioId to get_portfolio_context/analytics. Does not mention when not to use or list alternatives, but the guidance is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.